I didn't mean one tourist buying everything (which would be problematic no matter what the currency was), I meant in the aggregate. I've added an edit to my comment to clarify.
I'm actually curious how this will be implemented specifically. I guess (although I'm not well-informed on the ecosystem) that most of the places that let you do small cryptocoin transaction either use some smaller coin, or they must have some way of doing fractions of a bitcoin, right? In which case, the fraction system would have to be proprietary, I guess? I can't imagine the law required shopkeepers to use any particular proprietary exchange...
Its fundamental unit it the "Satoshi", of which there are 100 million in a "Bitcoin".